Hybrid ventilator

ABSTRACT

A ventilator ( 10 ) comprises a ventilator stator ( 12 ) for mounting to a structure and a ventilator rotor ( 14 ) for mounting and rotation with respect to the stator. One or more wind drivable elements ( 44 ) are mounted to the ventilator rotor. A motor ( 20 ) is provided for operation between the ventilator rotor and ventilator stator for selective motor-driven rotation of the ventilator rotor.

TECHNICAL FIELD

A ventilator is disclosed that is a hybrid of a wind driven ventilatorand a motor driven ventilator.

BACKGROUND ART

Ventilators can be employed to evacuate air and other gases fromenclosed spaces. Such enclosed spaces can include the roof space orinterior of commercial and domestic buildings, shipping containers,portable buildings and sheds, automobiles etc. The air and other gasesevacuated can include warm or heated gases, moist gases, gas containingcontaminants such as contaminated air or toxic fumes, stale gases(especially air) etc.

A ventilator known as a rotor ventilator comprises a rotor having aplurality of vanes which are oriented in use to capture ambient wind todrive (rotate) the ventilator rotor. In use, when the ventilator rotoris wind driven, air adjacent to the vanes is forced outwardly by therotating vanes, and this air is in turn replaced by air from theenclosed. space. This causes, in effect, a pumping out of air from thespace.

SUMMARY

In one aspect there is provided a ventilator comprising:

a ventilator stator for mounting to a structure;a ventilator rotor for mounting and rotation with respect to theventilator stator, the rotor comprising one or more wind-drivableelements; anda motor for operation between the ventilator rotor and ventilator statorfor selective motor-driven rotation of the ventilator rotor

The motor enables the ventilator rotor to be selectively driven, forexample, in low wind conditions and/or in excessive (ea. overly hot,moist or contaminated) enclosed space conditions

Reference herein to “wind-drivable elements” does not exclude theventilator rotor being rotated by means other than the wind or themotor. For example, the ventilator rotor may be driven by thermallygenerated gas currents exiting the enclosed space via the ventilator, oras a result of other gas pressurising means operating within theenclosed space (eg. conditioned or heat-induced airflow). Also,“wind-drivable” means the element can be driven by the wind.

The wind drivable element is typically a vane or a blade, but maycomprise another wind catchment device such as a cup, sail-shape etc.

Typically the rotor is oriented such that one or more of thewind-drivable elements is/are substantially exposed to the wind in use.More typically each element is arranged in use to be substantiallyexposed to the wind. Thus, the ventilator rotor may function in a normalwind-driven manner to receive a maximum prevailing wind force.

Whilst typically a motor may be mounted for operation between the rotorand stator, the motor may itself define the rotor and/or the stator ofthe ventilator. In this regard, and in the case of an electric motor,motor magnets may be eg. incorporated into the ventilator rotor and/orcoils into the ventilator stator. In other words the motor may beintegrated into the actual structure of the ventilator.

In one embodiment the motor connects the ventilator rotor to theventilator stator. In this regard, the motor rotor may be connected tothe ventilator rotor and the motor stator may be connected to theventilator stator. The motor can then act as a rotating mounting for theventilator rotor with respect to the ventilator stator. In addition, themotor also functions as a type of bearing for the ventilator rotor.

For example, when the ventilator rotor is caused by eg. the wind torotate with respect to the ventilator stator, it typically causes themotor rotor to also rotate therewith, and thus rotate with respect tothe motor stator.

However, the motor may alternatively be located separately to theventilator rotor and stator, or may even be located externally of theventilator. In either case, the motor can drive the ventilator rotor viaeg. a gear-train or belt drive etc.

In one form the ventilator stator may comprise a frame for mounting tothe structure.

In a first embodiment the motor stator may be directly mounted to theframe. Mounting the motor stator directly to the frame can enhancemechanical, constructional and operational efficiencies. For example,the ventilator can be provided in a more compact form, and the motor canbe housed entirely within the ventilator.

In a second alternative embodiment the motor stator can be mounted to ashaft which in turn is mounted to and projects from the frame. The shaftmay support the motor stator at a remote end thereof.

In one form the motor rotor can be mounted directly to the ventilatorrotor, resulting in the same efficiencies as with direct frame mountingof the motor stator.

Typically the motor is an “external rotor-type motor”, in which case themotor comprises a so-called “external rotor”. An external rotor is moreeasily able to be mounted to the ventilator rotor.

In the first embodiment, where the motor rotor and motor stator are eachdirectly mounted to corresponding parts of the ventilator, motorinternal bearings are typically provided that primarily absorb axialthrust loads but which can also absorb radial forces to which theventilator rotor may be subjected in use. Typically the motor internalbearings are selected such that the motor is able to resist twisting ortorsional forces applied to the ventilator by eg. variable windconditions/directions.

In the second embodiment the motor stator can be mounted to a flangelocated at the shaft remote end. A thrust bearing arrangement may thenbe provided to primarily absorb axial thrust loads but which can. alsoabsorb radial forces to which the ventilator rotor may be subjected. inuse. The thrust bearing arrangement includes a projection from the motorrotor that is supported for rotation within a recess at the shaft remoteend. Typically the projection is a shaft of the motor rotor that issupported in a bush which is in turn supported for rotation within aball bearing assembly located within the flange recess, with thisassembly thereby providing the thrust bearing. The thrust bearingarrangement can generally enhance the bearing function of the motorbetween the ventilator rotor and stator. Supporting the shaft in thismanner can also enable the motor to resist twisting or torsional forcesapplied to the rotor by eg. variable wind conditions/directions.

Typically an axis of the motor is aligned with a central ventilatorrotor axis to provide for a symmetrical and balanced operation of themotor and ventilator in use.

The motor rotor can be connected to a surrounding housing for the motor,with the motor housing in turn being connected to the ventilator rotor.

In one embodiment the housing is a sleeve that is directly mounted to aplate of the rotor, with the motor rotor being received and retainedwith the sleeve. The sleeve may alternatively be integrally formed withthe plate to project therefrom.

In another embodiment, the housing comprises a cap in which the motorrotor is received and retained, with the cap being mounted to theventilator rotor plate, to connect the motor rotor thereto.

Such arrangements provide a simple means for attaching the motor rotorto the ventilator rotor. The sleeve and cap can each also provide anenclosure for the motor rotor to prevent the ingress thereinto ofparticulate matter such as dust etc.

In one form the ventilator rotor comprises an in-use top plate, anin-use bottom plate, and a plurality of wind-drivable elements extendingbetween and respectively connected at opposing ends to the top andbottom plates.

The ventilator may further comprise a dome-shaped cover for the rotor.The dome-shaped cover can be mounted to the rotor top plate. Thedome-shaped cover can protect the rotor ventilator from environmentalconditions/elements, can increase the rigidity of the rotor, can providean aerodynamic profile to the rotor and can enhance the aesthetics ofthe rotor.

Typically the motor has low rotational resistance. In this regard. themotor may be “free-spinning”. Thus, when the motor functions as abearing in the ventilator (ie. by interconnecting the ventilator rotorand ventilator stator), the provision of low rotational resistance canenhance the motor's function as a bearing and can allow ventilator rotorrotation in a broad range of ambient wind conditions.

The motor can be electrical, being powered by either a direct oralternating current power supply (eg. from a mains source) or can bebattery driven. When the power supply is direct current, the motor maybe supplied power via one or more solar panels. Alternatively the motorcan be air/pneumatically driven, or may comprise an internal combustionengine or gas turbine etc.

A typical structure to which the ventilator stator is mounted is a roof,wall etc of an enclosed space of a building, or portable structure suchas a shed, house, automobile etc.

BRIEF DESCRIPTION OF DRAWINGS

Notwithstanding any other forms that may fall within the scope of theventilator as defined in the Summary, specific embodiments of theventilator will now be described, by way of example only, with referenceto the accompanying drawings in which:

FIG. 1 shows a perspective view of a first hybrid ventilator embodimentwith an optional dome-shaped cover removed therefrom;

FIG. 2 shows an underside perspective view of the ventilator of FIG. 1,showing a motor located therewithin;

FIG. 3 shows a plan view of the first ventilator embodiment of FIGS. 1and 2;

FIG. 4 shows a side sectional view of the ventilator of FIG. 3 taken onthe line A-A;

FIG. 5 shows a detail from the sectional view of FIG. 4;

FIG. 6 shows a plan view of a second hybrid ventilator embodiment with adome--shaped cover removed therefrom; and.

FIG. 7 shows a side sectional elevation of the ventilator of FIG. 6, butwith the dome-shaped cover in place.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring firstly to FIGS. 1 and 5, a first embodiment of a hybridventilator 10 is shown. This configuration. is typically employed withlarger ventilator installations.

The ventilator shown comprises two main bodies, a ventilator stator 12and a ventilator rotor 14.

The ventilator stator 12 comprises a throat 16 that is circular incross-section, and a frame in the form of sub-assembly 18 to locate andsupport a drive motor 20. In the embodiment of the hybrid ventilatordepicted in FIGS. 1 to 5, the motor directly connects the ventilatorrotor to the ventilator stator. The motor also functions as a bearingbetween the ventilator rotor and ventilator stator. Typically the motoris of low rotational resistance (eg. a free-spinning-type motor having arotor that is external to its stator) as described below.

The motor rotor comprises a motor body 21 for mounting to the ventilatorrotor. When the motor has an external rotor as shown, the motor body 21forms an integral part of the motor rotor.

The motor stator comprises a motor base 22 for supporting the motor body21 for rotation thereon. The motor stator is connected to the ventilatorstator 12 to provide for fixing of the ventilator to a flue or otheroutlet, and a base may be attached to the throat 16 that then adapts theventilator for mounting to various pitches of roofs, or a wall etc asrequired.

The ventilator stator sub-assembly 18 comprises a number of brackets 23(eg. four brackets are shown in FIG. 2). The brackets intersect at 24and are shaped at 25 for supporting receipt of the motor base 22 and amounting ring 26 affixed to both the base 22 and the brackets. Outerends of each bracket 23 are connected to the throat 16 via respectiverivets 27. Thus, the sub-assembly 18 mounts the motor stator to theventilator stator 12 and supports the motor in use. In addition, themotor stator is prevented from rotating in use when the motor isactivated.

Motor leads from either a direct or alternating current source, such asa mains power supply, battery, transformer, solar panel etc aretypically supported on the sub-assembly 18, and run along a givenbracket 23 to feed into the motor base 22.

The motor body 21 is mounted to and within a sleeve 30 forming a part ofthe ventilator rotor. The sleeve 30 is mounted to a circular plate 31,fastened to the underside of a ventilator rotor top plate 32 viafasteners 34. The sleeve 30 may alternatively be integrally formed withthe ventilator rotor.

The motor body comprises a peripheral flange 35 projecting out from itssidewall and adjacent to a base of the motor body 21. Flange 35 alignswith corresponding flanges 36 of the sleeve 30 and fasteners are thenintroduced through the flanges 35, 36 to fasten the motor body (ie. andthus fasten the motor rotor) to the ventilator rotor 14.

For additional stability a number of braces 37 (eg. five braces areshown in FIG. 2) can be provided that extend between the sleeve 30 andan outer periphery of ventilator rotor plate 32, with the braces beingfastened (eg. via rivets) to the underside of plate 32. Each brace 37 issized at a proximal end to snugly locate between the plate 31 and theflanges 36 of sleeve 30 (as best shown in FIG. 5).

Typically the motor 20 employs deep groove ball bearing rows/racesinternally between the motor rotor and stator. Such bearings can providea thrust bearing function to absorb primarily axial thrust loads butalso radial forces to which the ventilator may be subjected in use.Whilst this arrangement may not be used in some applications or withsome ventilator constructions, it is typically employed for largerventilators with more robust motors.

The deep groove ball bearing assembly can resist/accommodate axial andradial loads to which the ventilator rotor is subjected, and also resisttwisting or torsional forces applied to the ventilator rotor eg. byvariable wind conditions and directions.

The ventilator rotor comprises a turbine or impeller assembly 40. Theassembly 40 comprises the disc-shaped ventilator rotor top plate 32 andan annular-disc-shaped bottom plate 42. A plurality of vanes or blades44 extend between and are connected at respective ends to the top andbottom plates. In this regard, the vanes or blades are secured to thetop and bottom plates 32, 42 by bent over tabs 46 (FIGS. 1 to 3)inserted, through corresponding slots in the plates

The turbine assembly 40 may further comprise a dome for aesthetic and/oraerodynamic effects, although the installation of FIGS. 1 to 5 asdepicted is completely waterproof without the dome. A dome can also actas a protective cover against sun and dust.

In use the motor body 21 rotates on and is supported by motor base 22.As described above, the motor 20 is mechanically connected between andto each of the ventilator stator 12 and ventilator rotor 14 and thus,when activated, can be used to drive (or supplement the drive) of theventilator rotor 14. At the same time it can function as a rotationalbearing for the ventilator rotor 14.

In one mode of use, when evacuating air from an enclosed space, therotational output of the motor 20 is transferred to the ventilator rotor14, driving the turbine assembly (impeller) 40 to cause a ventilating(pumping) action. In this regard, air (or other gases) within theenclosed space in relation to which the ventilator 10 is located, iscaused to be drawn out of the enclosed space, the air/gas dischargingbetween the vanes/blades 44.

A unique feature of the ventilator 10 is the ability of the turbineassembly 40 to be powered by both ambient wind and/or the motor. In thisregard, the vanes/blades 44 each function as a working element in thatthey can induce a radial flow akin to that achieved from a centrifugalfan. The moving vanes/blades (ie. as a result of ambient wind and/or themotor) cause adjacent air (or gas) molecules to be rotated therewith. Asa result of the centrifugal acceleration imparted to the rotatingmolecules a progressively increasing outwardly directed radial force isimparted to the air molecules. The resultant centrifugal force expelsthe air molecules radially outwards from the ventilator 10, causing (orinducing) replacement air to be drawn into the throat 16 of theventilator and then into the voids between the vanes/blades. Thus, whenthe rotor is moving, a continuous flow of air through the ventilatorresults.

Referring now to FIGS. 6 and 7, a second embodiment of a hybridventilator 100 is shown. This configuration is typically employed withsmaller ventilator installations.

Again, the ventilator shown comprises two main bodies, a ventilatorstator 112 and a ventilator rotor 114. The stator 112 comprises a throat116 that is circular in cross-section, and a sub-assembly 118 to locateand support a drive motor 120.

In the embodiment of the hybrid ventilator depicted in FIGS. 6 and 7 themotor connects the ventilator rotor to the ventilator stator via a shaft124 (as described below). Again the motor is of a low rotationalresistance (free-spinning) type.

Again, the motor rotor comprises a motor body 121 and the motor statorcomprises a motor base 122 for supporting the motor body for rotationthereon. Again, the stator 112 can be adapted for fixing of theventilator to a flue, and may also be fitted to a base structure thatadapts the ventilator for mounting to a roof, wall etc as required.

The stator sub-assembly 118 comprises a bracket 123, a shaft 124 and aflange 126. The bracket 123 is connected to the throat 116 via rivets123A. The shaft 124 is in turn connected at one end to the bracket 123by screws 125A and at an opposite end to the flange 126 by screws 125B.The motor base 121 is secured to the flange 126 by fasteners 127 (eg.Taptite® screws), and is thereby connected through to the throat 116(stator). Thus, the sub-assembly 118 of bracket 123, shaft 124 andflange 126 mounts the motor 120 to the stator 112 and supports the motorin use. in addition, the motor base is prevented from rotating in usewhen the motor is activated.

Motor leads 128 from either a direct or alternating current source, suchas a battery, transformer, solar panel etc pass through an insulating(rubber) grommet 129 in the throat 116, and are also supported on thesub-assembly 118 and lead up to the motor 120 as shown, passing througha passage 124A in shaft 124 and an aperture 126A in the flange 126.

A turbine/impeller assembly 130 of the ventilator 100 comprises top andbottom plates 131,132, with a plurality of vanes or blades 134 extendingbetween and connected to the top and bottom plates. In this regard, thevanes are secured to the top and bottom plates 130,132 by bent over vanetabs 138 (FIG. 1).

The turbine assembly 130 further comprises a dome 136. The dome 136 issecured to the top plate 131 by either rivets 140 or by a series ofcold-formed type joints. The dome 136 acts as a protective cover for therotor ventilator to protect it against environmental conditions/elements(rain, sun etc), and also functions as a structural element to increasethe rigidity of the top plate 131. It also provides an aerodynamicprofile to the ventilator.

In addition to the mounting of the motor base 122 to the flange 126, themounting of the motor body 121 to the shaft 124 can employ a thrustbearing arrangement to primarily absorb axial thrust loads but alsoradial forces to which the ventilator rotor may be subjected in use.Whilst this arrangement may not be required in some applications ormotor constructions, it can be employed for smaller or less robust motortypes.

The thrust bearing arrangement includes a bush 142 that is located forrotation within a recess in the end of shaft 124 as shown. The bush 142is fastened to a motor shaft 144 projecting centrally out from the motorbody 121. The bush 142 is also mounted within a ball bearing assembly146, housed within the flange 126.

The ball bearing assembly functions as a thrust bearing. Thus, when themotor is activated, the ball bearing assembly 146 supports therewithinthe rotation of the bush 142 and motor shaft 144, andresist/accommodates any axial and radial loads to which the rotor issubjected. The bearing of motor shaft 144 also enables the motor toresist twisting or torsional forces applied to the rotor eg. by variablewind conditions and directions.

When the motor body 121 rotates on the motor base 122, the motor shaft144 connected to the motor body 121 rotates within and is supported bybearing 146.

To mount the motor body 121 to the rotor 114, a cap 150 is connected tothe motor body via set screws 152. A lower edge of cap 150 is thenfastened to the top plate 131 via a series of screws 154.

To shield the motor and bearing assembly against the ingress of airborneparticulate matter (eg. dust, moisture, fluids etc), and to prevent thedrop out of motor and bearing assembly lubricants, a shielding plate 160can be mounted to the flange 126 as shown, via a series of screws 162.

The motor 120 can thus be used to drive (or supplement the drive) of theventilator rotor 114.

The ventilator embodiment of FIGS. 6 and 7 may have similar modes of useto the ventilator embodiment of FIGS. 1 to 5.

Activation of the motor 20, 120 may be controlled by amicroprocessor-based control system, which can receive as inputs eg.ambient temperature, enclosed space temperature, humidity, ambient windvelocity etc, or can be pre-programmed. Thus, the motor can beselectively activated (eg. in low wind conditions on a hot day).

In contrast to powered fans, which are always enclosed in some form ofcowling, the ventilator 10, 100 exposes the impeller (and moreparticularly the vanes/blades) to any ambient wind conditions and canmake use of such conditions to achieve a ventilation effect. As bestshown in FIGS. 1 and 7, the vanes are oriented so as to be substantiallyexposed to the wind in use (ie. they are arranged to receive a maximumcomponent of prevailing wind when the wind (airflow) generally laterallyimpinges on the rotor ventilator). In this regard, the vanes are notshrouded by a cowling or the like and can function in a normalwind-driven manner.

The vanes/blades may be impelled by other than ambient wind or themotor. For example, the ventilator rotor may be driven by thermallygenerated gas currents exiting an enclosed space in relation to whichthe rotor ventilator is located, or by other gas pressurising means (eg.conditioned or heated airflow) operating within the enclosed space. Inthis regard, the ventilator can function as a controlled/controllablegas escape valve.

Whilst in the embodiments of FIGS. 1 to 7 the motor is shown connectingthe ventilator rotor to the ventilator stator, the motor may also belocated separately to the ventilator rotor/stator mounting. In thiscase, a separate bearing between the ventilator rotor and ventilatorstator is employed. Then, the motor may be located within the ventilatorand be connected by gear, belt drive etc to the ventilator rotor.

As a further alternative, the motor may be located externally of theventilator and be gear or otherwise connected to the rotor (eg. via adrive belt or chain). In yet another alternative, the motor may bemounted at or below the throat 16, 116 and connected to drive (rotate)the ventilator rotor through a suitable transmission arrangement(eg.gearing).

In a further variation, a one-way over-running clutch may be employed aspart of a transmission arrangement between the motor and ventilatorrotor to further reduce any motor resistance to ventilator rotorrotation, for example, when ambient wind conditions and/or thermalcurrents are the only power source.

The direct current source for the motor may employ voltages ranging from5 to 100 volts (eg. 12, 24, 48 volt batteries etc). The alternatingcurrent source may employ voltages ranging from 100 to 415 volts (eg.110 or 240 volt mains power supply) and may employ single phase or threephase power supply. Use of direct current enables batteries and solarpanels to provide power to the motor, whereas use of alternating currentenables a mains or grid electricity supply to provide power to themotor.

Instead of electrical power, the motor may be air/pneumatically or evensteam driven, or may comprise an internal combustion engine or gasturbine etc.

Components of the ventilator may be able to be retro-fitted to knownventilators that comprise a top plate and wind driveable vanes or bladesextending therefrom, although typically each hybrid ventilator ispurpose designed and manufactured.

An external faring may also be provided at the ventilator rotor bottomplate to enhance the aerodynamic profile of the ventilator.

Whilst the motor is typically a low rotational resistance(free-spinning) type, it may have relatively high torque output,especially for larger ventilator installations. The motor may have atorque in the range of 1-2 Nm. In this regard, the motor may have a hightorque to rpm ratio, with a larger ventilator installation operating atspeeds in the range of 200-400 rpm, and smaller ventilator installationsoperating at speeds in the range of 600-800 rpm.

In a further variation the motor may be integrated into the actualstructure of the ventilator. In. this regard, the motor may itself beconstructed and shaped to define the ventilator rotor and/or theventilator stator. In the case of an electric motor, motor magnets maybe incorporated into the ventilator rotor and/or coils into theventilator stator.

Whilst specific embodiments of the rotor ventilator have been described,it should be appreciated that the rotor ventilator can be embodied inmany other forms.

1-19. (canceled)
 20. A selectively wind- or motor-driven ventilator,comprising: a stator configured to be mounted to a structure; a rotorhaving a plurality of wind-drivable elements that are substantiallyexposed to the wind when in use, said rotor rotatable with respect tosaid stator when said rotor is caused to rotate by the wind when in use;a low rotational resistance motor mounted between the stator and rotorand arranged such that, when the motor is not activated, the wind isable to rotate the rotor with respect to the stator, and when the motoris activated, the motor rotates the rotor with respect to the stator.21. A ventilator as claimed in claim 20 wherein the low rotationalresistance motor comprises an external rotor arranged such that, whenthe motor is activated, the motor rotates the external rotor whichthereby rotates the ventilator rotor with respect to the ventilatorstator.
 22. A ventilator as claimed in claim 21 wherein the externalrotor of the motor is directly connected to the ventilator rotor.
 23. Aventilator as claimed in claim 20 wherein the motor contains a motorstator that is directly connected to the ventilator stator.
 24. Aventilator as claimed in claim 20 wherein each wind-drivable element isa vane or blade.
 25. A ventilator as claimed in claim 20 wherein theventilator stator is part of a frame configured to be mounted to thestructure, and the motor contains a motor stator that is fixed to theframe.
 26. A ventilator as claimed in claim 25 wherein the motor is anexternal rotor motor, with a body of the motor defining the externalrotor of the motor that rotates with the ventilator rotor in use, andwith a base of the motor defining the motor stator that is fixed to theframe.
 27. A ventilator as claimed in claim 26 wherein the motor body isconnected to a surrounding motor housing and the motor housing isconnected to the ventilator rotor.
 28. A ventilator as claimed in claim27 wherein the ventilator rotor has an in-use top plate and an in-usebottom plate, and wherein the plurality of wind-drivable elements extendbetween and are connected at respective opposing element ends to saidtop and bottom plates, and wherein the motor housing is connected to thetop plate, thereby rotating the rotor.
 29. A ventilator as claimed inclaim 20 wherein the ventilator stator is part of a frame configured tobe mounted to the structure, with a shall mounted to and projecting fromthe frame, the shaft supporting the motor at a remote end thereof.
 30. Aventilator as claimed in claim 29 wherein the motor has a motor bodythat rotates with the ventilator rotor, and has a motor base that is astator fixed to the frame.
 31. A ventilator as claimed in claim 30wherein the motor base is mounted to a flange located at the shaftremote end, with a projection from the motor body being supported forrotation within a recess at the shaft remote end.
 32. A ventilator asclaimed in claim 31 wherein the projection is a shaft of the motor bodythat is supported tor rotation in a bush which is in turn supported forrotation within a ball bearing assembly located within the flangerecess.
 33. A ventilator as claimed in claim 20 wherein the motorcomprises a ball bearing that functions as a thrust bearing.
 34. Aventilator as claimed in claim 20 further comprising a control systemthat selectively activates the motor.
 35. A ventilator as claimed inclaim 34 wherein the control system comprises a microprocessor basedcontroller that selectively activates the motor when receiving inputsselected from the group consisting of ambient temperature, enclosedspace temperature, humidity, and ambient wind velocity.
 36. A ventilatoras claimed in claim 20 wherein said structure is an enclosed space, abuilding roof, a house, a portable dwelling, a shed, or an automobile.37. A ventilator as claimed in claim 20 wherein the ventilator rotor hasan in-use top plate and an in-use bottom plate, and wherein theplurality of wind-drivable elements extend between and are connected atrespective opposing element ends to said top and bottom plates.
 38. Aventilator as claimed in claim 20 wherein the motor is located at leastpartially within the rotor.
 39. A ventilator as claimed in claim 20, theventilator having a rotational axis, with the motor located on therotational axis.